Showing papers in "Journal of AOAC International in 1976"

Reference Raman spectra of ten phosphorus-containing pesticides.

Abstract: The Raman spectra of malathion, ethion, methyl parathion, parathion, EPN, 0,0-diethyl-0-(2,4-dichlorophenyl) phosphorothioate, dichlorvos, mevinphos, tributyl phosphorotrithioite, and 2,4-dichlorobenzyltributylphosphonium chloride have been recorded. These spectra are presented, along with tables giving values for the frequencies.

Determination of sterigmatocystin in corn and oats by gel permeation and high-pressure liquid chromatography.

Abstract: Corn and oats samples are extracted with acetonitrile-water, followed by partition of the extract against hexane, transfer to chloroform, and elution from a silica gel column. The extract is purified by gel permeation chromatography on an automatic instrument. Reverse phase high-pressure liquid chromatography, using a 254 nm ultraviolet detector and 0.1 M KH2PO4-acetonitrile (7+5) as the mobile phase, is used for quantitation. The average recovery from 6 samples of corn to which 0, 25, 50, and 100 mug sterigmatocystin/kg had been added was 59%, with a coefficient of variation of 8.4%. The average recovery from oats fortified at the same levels was 74%, with a coefficient of variation of 12%. A confirmation procedure based on hemiacetal derivative formation on a thin layer chromatographic plate is also described.

Substances interfering with the gas-liquid chromatographic determination of T-2 mycotoxin.

Abstract: Two substances interfering with the gas-liquid chromatographic (GLC) detection of T-2 mycotoxin were identified as 1-glyceryl-monooleate and 1-glycerylmonolinoleate. These monoglycerides are natural products formed by species of Fusarium growing on cereal grains and are also additives contained in liquid vegetable and animal fats added to the feed mixture. The monoglycerides can be removed from the analytical sample by resolution by thin layer chromatography prior to separation by GLC. Trimethylsilyl ether derivatives of the monoglycerides and T-2 toxin have almost identical retention times on 3% OV-1 columns, whereas the trifluoroacetyl and pentafluoropropionyl derivatives give baseline separation on the same column. The monoglycerides can be misidentified as the T-2 toxin in analyses involbing GLC.

Identification of some analogs of the hallucinogen phencyclidine.

Abstract: The drugs 1-[1-(2-thienyl)cyclohexyl]piperidine, 1-[1-2-thienyl)cyclohexyl]pyrrolidine, 1-(-phenylcyclohexyl) morpholine, and 1-(1-phenyleyclohexyl) pyrrolidine are identified by spectroscopic techniques The ultraviolet and proton magnetic resonance spectra of analogs are similar, but mass and infrared spectra are distinctly different, and reference spectra are provided Gas-liquid ant thin layer chromatographic systems for the analysis are discussed

Gas-liquid chromatographic determination of levamisole residues in bovine milk.

Abstract: A gas-liquid chromatographic (GLC) method is described for determining residues of levamisole, (1-)-(2,3,5,6-tetrahydro-6-phenylimidazo [2,1-b] thiazole), in milk. Levamisole is extracted from an alkaline milk sample with water-saturated ethyl acetate. After co-extractives are removed by various partitionings, the levamisole concentration is measured by GLC by using an alkali (RbSO4) flame ionization detector, vs. an external standard. This method is satisfactory for determining levamisole residues as low as 0.01 ppm in bovine milk. Apparent residues in control milk samples averaged less than 0.001 ppm. Recoveries of 0.01-2.0 ppm added levamisole ranged from 86.5 to 113%. Animals treated with various Tramisol formulations showed apparent levamisole residues below the validated sensitivity of the method (0.01 ppm) at sampling periods exceeding 48 hr.

Collaborative Study of Accelerated Development of Latent Fingerprint Images on Paper by Application of Steam

Abstract: Nine latent fingerprint examiners participated in a collaborative study in the use of a steam iron to accelerate chemical development of latent images on bond and newsprint papers treated with a 0.5% solution of ninhydrin in acetone. Four latent images were placed on each paper by the Associate Referee during an 8 hr period. The papers were paired and numbered 1, 2, and 3. Three pairs were mailed to each collaborator who treated Pair 1 by dipping, Pair 2 by brushing or swabbing, and Pair 3 by spraying. After air-drying, the papers were subjected to heat and steam from a household steam iron until the images developed. The average time for developing all images was 5.8 min/paper. Of the total images available, 92.1% were developed to some degree; 47.9% of these images or 43.5% of all images were identified by the collaborators. The method has been adopted as offical first action.

Detection of O,O-diethyl-O-(2,5-dichlorophenyl) phosphorothioate and O,O-diethyl-O-(3,6-dichloro-2-pyridyl) phosphorothioate in meat fat.

Abstract: Two previously unreported organophosphorus residues have been detected in meat fat. The first, O,O-diethyl-O-(2,5-dichlorophenyl) phosphorothioate, apparently results from the debromination of bromophos-ethyl, while the other, O,O-diethy-O-(3,6-dichloro-2-pyridyl) phosphorothioate, presumably arises by the monodechlorination of chlorpyriphos. Mass spectral evidence is presented in support of the assigned structures and gas-liquid chromatographic retention data for the residues and their oxygen analogs are provided.

Collaborative study of the spectrophotometric determination of procainamide hydrochloride.

Abstract: The USP analysis for procainamide-HCl is titrimetric and relatively nonspecific, capsule and tablet dyes may interfere, and the method is not applicable to coated tablets. In the spectrophotofluorometric method the sample deteriorates when exposed to a xenon source. In the ultraviolet spectrophotometric method reported here, the sample is dispersed in acid medium, possible interferences are extracted in chloroform, base is added, procainamide is extracted in chloroform, the residue is dissolved in sodium hydroxide, the compound is measured by absorption at 272 nm and comparison with a standard. Recoveries of standards added to capsule, tablet, and injection composites ranged from 99.3 to 102%. Twelve collaborators reported duplicate assay results for all 3 dosage forms with per cent standard deviations for 5 samples ranging from 1.01 to 1.27%. The method has been adopted as official first action.